Ustekinumab trough level and perianal fistulizing Crohn’s disease

In the context of perianal fistulizing Crohn's disease (PFCD), ustekinumab (UST) trough concentrations play a critical role in predicting clinical and radiological remission. A recent study has identified optimal trough levels for achieving fistula remission and managing the condition effectively.

The study found that UST trough concentrations ≥3.95 µg/mL at weeks 16/20 are predictive of fistula clinical remission, with an area under the curve (AUC) of 0.791, as determined by receiver operating characteristic (ROC) analysis. This threshold serves as a benchmark for therapeutic drug monitoring (TDM), helping to optimize dosing strategies for patients with PFCD. Additionally, the study highlighted that UST concentrations ≥2.75 µg/mL are associated with intestinal remission, indicating that fistulizing and luminal Crohn's disease may require different pharmacokinetic targets.

The findings underscore the importance of TDM in managing PFCD, as maintaining adequate UST trough levels can improve clinical outcomes, including fistula healing and systemic inflammation control. However, achieving and maintaining these trough levels may require dose adjustments or increased dosing frequency, which could lead to higher treatment costs. Despite this, the clinical benefits, such as reduced relapse rates, improved healing, and enhanced quality of life, justify the consideration of TDM in routine clinical practice for PFCD patients.